The bloodshed came on the heels of a string of attacks in Turkey, blamed on jihadists but also on Kurdish rebels.

The bomb aimed at a convoy of military service vehicles, Ankara governor Mehmet Kiliclar said, quoted by the CNN-Turk and NTV channels.

Plumes of smoke were seen rising over an area and the powerful blast was heard all over the city, sending residents to their balconies in panic, an AFP correspondent said. Ambulances and fire engines were sent to the scene, which is near the Turkish military headquarters and the parliament.

NTV television said the explosion happened near a residential block for top-level military staff. The spokesman for the ruling Justice and Development Party (AKP), Omer Celik, said he strongly condemned the attack, Turkish media reported.

There was no immediate indication about who carried out the attack, but the Islamic State group has been blamed for a string of bombings in the country since the middle of last year.

The attack targeted a convoy of military service vehicles, Ankara governor Mehmet Kiliclar said, quoted by the CNN-Turk and NTV channels.

Capital on alertThe capital was already on alert after 103 people were killed on October 10 when two suicide bombers blew themselves up in a crowd of peace activists in Ankara, the bloodiest attack in the country's modern history.

The PKK launched an insurgency against the Turkish state in 1984, initially fighting for Kurdish independence although now more for greater autonomy and rights for the country's largest ethnic minority.

The conflict, which has left tens of thousands of people dead, looked like it could be nearing a resolution until an uneasy truce was shattered in July.

Ankara has also been carrying out air strikes against Syrian Kurdish fighters across the border wartorn Syria since the weekend.

A Kurdish splinter group, the Freedom Falcons of Kurdistan (TAK), claimed a mortar attack on Istanbul's second international airport on December 23 which killed a female cleaner and damaged several planes.